Device for overcoming dead-centers.



No. 678,603.' Patented Iuly I6, 190|.

- S. B. WICKERSHAM.

DEVICE FOR OVERGOMING DEAD GENTEBS.

(Application led Feb. 2B, 1901.7) (No Model.)

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STEPHEN I3. IVIOKERSHAM, OF PHOENIX, ARIZONA TERRITORY.

DEVICE lli-'OR OVERCOIVIING DEADm-CNTERS.

SPECIFICATION forming part of Letters Patent No. 678,603, dated July 16, 1901.

Application filed February 28, 1901. Serial No. lMLSZO. (llo model.)

T0 @ZZ whom, it may concern:

Be it known that I, STEPHEN B. WICKER- sHAM, a citizen of the United States, residing at Phoenix, in the county of Maricopa and Territory of `Arizona, have invented certain new and useful Improvements in Devices for Overcoming DeadLOenters; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art tdwhich it appertains to make and use the same.

The invention relates to a device for overcoming dead-centers, and is particularly designed as an attachment for sewing-machines, whereby the machine may be instantly started without the necessity of turning the iiywheel.

The object of the invention is to providea simple and eifective device of this character which will prevent backward running of the machine and which maybe conveniently operated to secure the desired result.

The invention consists of certain features of construction, combination, and arrangement of parts, as will be hereinafter more fully described, and particularly pointed out in the appended claim.

In the accompanying drawings, Figure lis a front elevation of the frame and drive mechanism of a sewing-machine, showing the ap` plication of the invention thereto. Fig. 2 is a cross-section, on an enlarged scale, of the band-wheel of the drive mechanism and cooperating parts of the invention; and Figs. 3 and et are views looking toward opposite sides of the loose ratchet-disk, showing the retractile spring and fixed disk of the clutch mechanism.

Referring now more particularly to the drawings, l indicates the pedal, 2 its rod or shaft, 3 the band-wheel, I its supporting stud or shaft, and 5 the pitman or connecting rod of the drive mechanism of a sewing-machine of ordinary construction. The stud or shaft 4 may be either stationary orrevoluhle and the band-wheel 3 mounted to revolve thereon or fixed thereto to turn therewith at the will or option of the manufacturer.

The numeral 6 indicates the casing of the herein-described invention, in which is inclosed a disk 7, having a grooved periphery, to which is connected one end of a cord 8,

connecting said disk with an auxiliary pedal 9 on the rod or shaft 2. This disk 7 is loosely mounted on a hub l0, which is :rigidly con.- nected to the shaft 4, and on this hub is also mounted a disk l1, which is mounted to rotate with the wheel 3, either by rigidly securing it to said wheel or to the said hub 10. The cord 8 moves freely in an opening 12, formed in the casing 6.

The loose disk 7 is recessed upon one side to receive a coiled retractile spring 13, one end of which is secured thereto and the other end to the casing 6. The purpose of this spring is to maintain the parts in their normal operative positions. The disk 7 is also recessed upon its opposite side to receive the disk ll and is formed with internal ratchet-teeth 14C, with which engage pivoted dogs or pawls 14 on said disk l1, this construction constituting a clutch connection between the two disks which causes the disks to move in unison in one direction. The pawls le', of which not less than three nor more than iive are employed, are equidistant and are nearly counterbalanced by extensions l5 on the opposite side of their pivots from their hooked ends. Pins 16 limit the retracting movement of the pawls. When the disk 7 is moved in the direc-tion of the arrow,Fig. l,the ratchetteeth engage the pawls, and by this means both disks 7 and ll are clutched together to move in unison, and motion is also imparted to the band-wheel 3 to start the operation of the drive mechanism. In this direction` of movement of the disks the spring 13 is wound up and reacts to restore the disk 7 to its original position, the ratchet-teeth riding over the pawls in this backward movement of said disk 7. Upon the operation of the drive mechanism the disk 7 remains stationary, while the disk 1l rotates with the band-wheel 3.

In operation when the auxiliary pedali) is depressed the disk 7 is turned in the direction to clutch the disk l1, and power is imparted to the band-wheel 3 to move the parts past the center and start the operation of the drive mechanism. Upon then operating the pedal l a continuous motion in aforward direction will be communicated to the drive mechanism in a manner readily understood. The pawl-and-ratchet connection between the two disks 7 and .ll prevents IOO backward motion of the drive mechanism, While the spring 13 restores the disk 7 to its normal position for a repetition of the operation above described.

It Will thus be seen that the invention provides a simple and conveniently-operated device which accomplishes the desired purpose in an effective manner.

AHaving thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

In a sewing-machine, the combination With a pedal and pedal-shaft, of the connectingrod connected thereto, a stud or shaft mounted upon the frame of the machine, a belt- Wheel mounted upon said stud or shaft and having a crankpin connected to said conpecting-rod, a casing having a hub or sleeve rigidly connected to the stud or shaft, a disk mounted loosely within the casing and grooved or recessed upon its opposite sides, the Wall of one of the recessed sides being provided with ratchet-teeth, a second disk arranged within the latter-named recess and rigidly connected with the belt-Wheel to rotate therewith, pawls upon the rotating disk to engage the ratchet-teeth of the loose disk, said paWls having counterbalancing eXtensions, pins upon the rotating disk coacting with said extensions to limit the retracting movement of the pawls, a spiral spring arranged Within the other recessed face of the loose disk and connected at one end thereto and at the other end to the casing to return the loose disk to its normal position, a cord connected With the loose disk and Working through a slot in the casing, and an auxiliary pedal mounted upon the pedal-shaft and connected to said cord for imparting'movement to the loose disk, substantially as described.

In testimony whereof I have hereunto set my hand in presence of tWo subscribing Witnesses.

STEPHEN B. WICKERSl-IAM.

IVitnesses:

ALBERT W. STAcY, JOSEPH GLADUE. 

